Week in Review: January 5–9

Jan 9, 2015

Tracy Vence

NORTHEASTERN UNIVERSITY, SLAVA EPSTEINA new antibiotic isolated from microbial “dark matter”—species that cannot be cultured in the lab—has shown potent activity against gram-positive bacteria, with no signs of resistance, according to a study published in Nature this week (January 7).Researchers from Northeastern University in Boston unearthed teixobactin from a soil-dwelling bacterium in collaboration with their colleagues at the Cambridge-based NovoBiotic Pharmaceuticals.

“Teixobactin demonstrates that there are compounds that may have exceedingly low probability of resistance, providing us with a new strategy for antibiotic development,” Northeastern’s Kim Lewis, who led the study, told The Scientist.

That the researchers isolated the antibiotic-producing bacteria and then grew it in a chamber within the soil for further study “is a very clever technique,” said Robert Austin of Princeton University was not involved in the study. “The bacteriology community needs to get away from culturing bacteria on agar plates, because this will not lead to new antibiotics.”

INSTITUTE OF FOOD RESEARCH, KATHRYN CROSS AND NIKKI HORNCommensal Bacteroidetes bacteria outmaneuver antimicrobial peptides released by their mammalian hosts largely because of a gene that encodes a bacterial cell membrane-modifying enzyme, researchers from the Yale University School of Medicine and their colleagues reported in Science this week (January 8).

“We didn’t understand how you could have a host response that seems to be general but also commensal microbes showing this stability in the same circumstances where pathogens are cleared,” study coauthor Andy Goodman of Yale told The Scientist.

So the researchers systematically tested both commensal and pathogenic species found in the mouse gut, homing in on one gene, lpxF, which appeared to confer protection against the host-released antimicrobial peptides.

“Most folks didn’t anticipate that the commensal microbes would be resistant to antimicrobial peptides,” said Charles Bevins of the University of California, Davis, School of Medicine who was not involved in the work.